从下划线中的数组中删除值 [英] Remove value from array in Underscore

问题描述

为什么下划线没有超级简单的remove函数?

Why isn't there a super simple remove function in underscore?

var arr = [1,2,3,4,5];
_.remove(arr, 5);

当然我可以使用 reject 或 without ......但它们都不是破坏性的.我错过了什么吗?

Sure I could use reject or without... but neither of them are destructive. Am I missing something?

我想我会用老式的方式来做...

I guess I'll do it the old fashioned way...

arr.splice(arr.indexOf(5), 1);

呃

推荐答案

说明

这是因为 Underscore 为 JavaScript 提供了函数式概念，而函数式编程的关键概念之一是 参考透明度.

本质上，函数没有副作用，并且对于给定的输入总是返回相同的输出.换句话说，所有函数都是纯.

Essentially, functions do not have side-effects and will always return the same output for a given input. In other words, all functions are pure.

从数组中移除元素确实是给定输入的可预测结果，但结果将是副作用而不是返回值.因此，破坏性函数不适合函数范式.

Removing an element from the array would indeed be a predictable result for the given input, but the result would be a side-effect rather than a return value. Thus, destructive functions do not fit into the functional paradigm.

已在 Stack Overflow 此处上详细讨论了从 Underscore 中的数组中删除值的正确方法.作为旁注，当使用 without、reject 或 filter 时，如果您只想从数组中删除一个项目的单个实例，您将需要唯一标识它.所以，以这种方式:

The correct way to remove values from an array in Underscore has already been discussed at length on Stack Overflow here. As a side note, when using without, reject or filter, if you only want to remove a single instance of an item from an array, you will need to uniquely identify it. So, in this manner:

arr = _.without(arr, 5);

您将从arr中删除所有5的实例.

这篇关于从下划线中的数组中删除值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！